Palladium-mediated strategies for functionalizing the dihydroazulene photoswitch: paving the way for its exploitation in molecular electronics

TY - JOUR

T1 - Palladium-mediated strategies for functionalizing the dihydroazulene photoswitch

T2 - paving the way for its exploitation in molecular electronics

AU - Jevric, Martyn

AU - Broman, Søren Lindbæk

AU - Nielsen, Mogens Brøndsted

PY - 2013/5/3

Y1 - 2013/5/3

N2 - The dihydroazulene (DHA)/vinylheptafulvene (VHF) photo/thermoswitch has attracted interest as a molecular switch for advanced materials and molecular electronics. We report here two synthetic approaches using palladium catalysis for synthesizing dihydroazulene (DHA) photoswitches with thioacetate anchoring groups intended for molecular electronics applications. The first methodology involves a Suzuki coupling using tert-butyl thioether protecting groups. Conversion to the thioacetate using boron tribromide/acetyl chloride results in the formation of the product as a mixture of regioisomers mediated by a ring-opening reaction. The second approach circumvents isomerization by the synthesis of stannanes as intermediates and their use in a Stille coupling. Although fully unsaturated azulenes are formed as byproducts during the synthesis of the DHA stannanes, this approach allowed the regioselective incorporation of the thioacetate anchoring group in either one of the two ends (positions 2 or 7) or at both.

AB - The dihydroazulene (DHA)/vinylheptafulvene (VHF) photo/thermoswitch has attracted interest as a molecular switch for advanced materials and molecular electronics. We report here two synthetic approaches using palladium catalysis for synthesizing dihydroazulene (DHA) photoswitches with thioacetate anchoring groups intended for molecular electronics applications. The first methodology involves a Suzuki coupling using tert-butyl thioether protecting groups. Conversion to the thioacetate using boron tribromide/acetyl chloride results in the formation of the product as a mixture of regioisomers mediated by a ring-opening reaction. The second approach circumvents isomerization by the synthesis of stannanes as intermediates and their use in a Stille coupling. Although fully unsaturated azulenes are formed as byproducts during the synthesis of the DHA stannanes, this approach allowed the regioselective incorporation of the thioacetate anchoring group in either one of the two ends (positions 2 or 7) or at both.

U2 - 10.1021/jo400362u

DO - 10.1021/jo400362u

M3 - Journal article

C2 - 23586425

SN - 0022-3263

VL - 78

SP - 4348

EP - 4356

JO - Journal of Organic Chemistry

JF - Journal of Organic Chemistry

IS - 9

ER -